Numerous medications cannot be stored in liquid form, but have to be dissolved in sterile water or another type of solvent before being used. It has been known for some time to on the one hand prepare a medication as a dry substance and on the other hand a solvent in separate injection bottles. The latter are closed with a closing element that can be penetrated by an injection needle. When using this, the closing element of the bottle containing the water is pierced with a steel cannula placed on top of a syringe and the water then extracted into the syringe. After pulling out the steel cannula it is entered into a closing element of a bottle, which contained the medication as a dry substance, and the water is fed into this bottle from the syringe. Afterwards the bottle is shaken until the medication has dissolved and the dissolved medication is drawn into the syringe with the same cannula. This procedure is relatively elaborate and dangerous due to operation of the steel cannula.
U.S. Pat. No. 6 558 365 B2 discloses a medical transfer device consisting primarily of two caps, each bottom of which contains one spike extending into the inner part of the cap. The outer surface of one of the caps has a pin with a conical outer surface, extending into a conical recess of a pin placed on the bottom of the other cap. A connection canal runs through the spikes and the pins. The cylindrical parts of the caps are split and can therefore be widened radially in such a way that each of the caps can be snapped open across the bulge of the neck of a bottle. The length of the spikes is selected so that the closing element of the bottle is pierced during this process. First, one of the caps is snapped onto the neck of a bottle containing either water or another solvent, so that the appropriate spike pierces the closing element of the bottle and reaches the inside of the bottle. Then, the other cap is snapped onto the neck of a bottle containing a medication in the form of a dry substance. Afterwards, both caps are connected to one another by their spikes. Then the fluid is filled into the bottle with the dry substance and the latter dissolved in the fluid. Then the cap belonging to the bottle with the dissolved medication is removed, so that the complementary conical pin of a syringe can be inserted into the conical receiving element of the other cap and the medication can be extracted.
However, this known design has several disadvantages. One of the disadvantages is that the caps could be mistakenly switched when placed on the necks of the bottles, creating the danger that the cap with a conical pin will remain on the bottle with the dissolved medication, which pin provides no connection with the conical pin of a syringe, and the medication cannot be extracted. Afterwards a cannula has to be placed on the syringe, which can lead to injuries caused by the tip of the cannula, particularly when the patient is administering the injection, which is most often the case.
U.S. Pat. No. 6 070 623 discloses a medical transfer device with a first tubular-shaped part that is movable inside of a second tubular-shaped part between an inserted and extracted position. A holding part is connected to the first tubular-shaped part and has a conical receiving element for connecting means for detachable and sealed connection of the conical receiving element with a container holding the fluid or rather the solvent. It is formed by a syringe featuring a cylindrical wall and a movable rod inside of it, which is movable by means of a piston rod.
There is a cannula on the opposite side of the conical receiving element on the second tubular-shaped part, through which a canal extends from the inner side of the conical receiving element to its tip.
During usage of this known device, first sterile water or a sterile solution is drawn up and the anterior conical pin of the needle is placed in the conical receiving element in the first tubular-shaped part. Afterwards, the second tubular-shaped part is placed on the neck of a bottle containing a dry, powder-shaped medication and featuring a pierceable closing element and the cannula of the syringe pierces the closing element of the bottle containing the medication. Then, by using the syringe, the fluid inside of the syringe is injected into the container containing the medication and the medication is dissolved in the fluid. The container with the medication is at the bottom and the syringe at the top during this process; the device is turned upside down in a way that the fluid containing the medication is above the spike, so that fluid containing the medication can be extracted by the syringe. Then the connective pin of the syringe is separated from the conical receiving element of the first tubular-shaped part and an injection syringe is placed on the connective pin of the needle, so that the medication can be injected into the body of a patient. Attaching the injection needle can lead to injuries caused by the tip of the needle, just as with the first device, particularly when the patient is administering the injection, which is most often the case. Also, another disadvantage is that the penetration depth of the cannula during injection and extraction of the fluid depends on how it is handled.